Ethernet controller with integrated TSN/AVB control point and time slave

ABSTRACT

An Ethernet adapter module for interfacing a network endpoint device to an Ethernet network is disclosed. The Ethernet adapter module includes an Ethernet medium access controller (MAC) and an Ethernet physical layer device (PHY). The Ethernet MAC includes a processor and Time Sensitive Networking and/or Audio Video Bridging (TSN/AVB) state machines that cooperate with the processor to (1) identify a TSN/AVB request from the network endpoint device, and (2) discover a network topology along which to transfer data between the network endpoint device and a second network endpoint device in accordance with a predetermined Quality of Service (QoS). The Ethernet PHY is coupled to the Ethernet MAC and includes timestamp logic to apply a timing reference to the data being transferred.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part that claims priority to U.S.application Ser. No. 15/276,250, filed Sep. 26, 2016, entitled ETHERNETCONTROLLER WITH INTEGRATED TSN/AVB CONTROL POINT AND TIME SLAVE, whichis a Continuation-In-Part that claims priority to U.S. application Ser.No. 14/858,918, filed Sep. 18, 2015, entitled ETHERNET CONTROLLER WITHINTEGRATED AVB CONTROL POINT AND TIME SLAVE, all of which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The disclosure herein relates to communications systems, and morespecifically to local area network systems and methods.

BACKGROUND

Multi-media data streaming represents an increasingly large portion ofoverall Internet traffic. One conventional method to enable multi-mediadata transfers over a proprietary high speed connection with veryprecise timing and high link stability involves an SDI interface. TheSDI interface generally provides for data speeds up to 6 Gbps.

Recently, to achieve the same high precision and stable link quality,Time Sensitive Networking (TSN) and Audio Video Bridge (AVB) standardshave been ratified to enable high-speed synchronized multi-media datatransfers over high-speed local area networks, such as Ethernet and10GBASE-T. With this new approach, conventional adapters (i.e. Ethernetand WiFi) are used to transfer high precision, broadcast qualitymulti-media, instead of proprietary SDI ones. As with any othermultimedia distribution system, processing functions on the end point(for example a computer, laptop, tablet, automotive embedded device,video disc recorder, transcoder, or video end point) associated with themultimedia data are often carried out by large, high-power processors.This may be undesirable depending on the application. When themultimedia data is carried by such high-power processors, they need toremain on all the time to be able to carry the data, resulting in theinability of the end point to enter sleep mode, thus causing increasedpower consumption. Another concern associated with TSN and/or AVBstandards running on these processors, is the need to support thecomplete TSN and/or AVB protocol stack in the software installed on theOperating System (OS), with all the potential compatibility problems andlack of essential TSN and/or AVB services associated with this.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure are illustrated by way of example, and notby way of limitation, in the figures of the accompanying drawings and inwhich like reference numerals refer to similar elements and in which:

FIG. 1 illustrates a high-level block diagram of a TSN/AVB domain ofinterconnected TSN/AVB end point devices and a TSN/AVB bridge.

FIG. 2 illustrates a TSN/AVB end point device of FIG. 1 in furtherdetail, together with a network adapter card.

FIG. 3 illustrates a network adapter card for use in the system of FIG.2.

FIG. 4 illustrates a flowchart of steps for one embodiment of a methodfor processing multi-media data in an Ethernet network.

DETAILED DESCRIPTION

Embodiments of networking systems, adapter cards and associated methodsare disclosed herein. One embodiment of an Ethernet adapter module forinterfacing a network endpoint device to an Ethernet network isdisclosed. The Ethernet adapter module includes an Ethernet mediumaccess controller (MAC) and an Ethernet physical layer device (PHY). TheEthernet MAC includes a processor and offload hardware that togetherwith the processor perform audio video discovery, enumeration,connection management and control (AVDECC) for media devices connectedto Ethernet network and available inside the TSN/AVB domainfunctionality (using IEEE 1722.1 standard terminology). Additionalframing and de-framing of the multimedia data per various encapsulationstandards used may also be part of the offload hardware. The EthernetPHY is coupled to the Ethernet MAC and includes timestamp logic to applya timing reference to the data being transferred.

In a further embodiment, a system is disclosed including a first TSN/AVBnetwork endpoint device and an Ethernet adapter module for interfacingthe first TSN/AVB network endpoint device to an Ethernet network. Theendpoint device has processing hardware and a control applicationinterface. The Ethernet adapter module includes an Ethernet mediumaccess controller (MAC) and an Ethernet physical layer device (PHY). TheEthernet MAC includes a processor, and Time Sensitive Network (TSN)and/or Audio Video Bridging (AVB) state machines that cooperate with theprocessor to (1) identify a TSN/AVB request (a TSN and/or an AVBrequest) from the network endpoint device, and (2) discover a networktopology along which to transfer data between the network endpointdevice and a second network endpoint device in accordance with apredetermined Quality of Service (QoS). The PHY is coupled to theEthernet MAC and includes timestamp logic to apply a timing reference tothe data being transferred.

In an additional embodiment, a method of operation between a TSN/AVBnetwork endpoint device and an Ethernet network adapter is disclosed.The method includes opening an application with the TSN/AVB networkendpoint device, the application requesting TSN/AVB services andoffloading processing of the TSN/AVB services to the Ethernet networkadapter. The processing of the TSN/AVB services includes TSN/AVBdiscovery, enumeration and connection management, reserving streams orredundant streams for transferring the TSN/AVB data, and timestampingthe TSN/AVB data.

FIG. 1 illustrates a collection of devices that are interconnected viaEthernet to form a network, generally designated 100. The networkincludes a Time Sensitive Network (TSN) and/or Audio Video Bridge (AVB)102 that provides time-synchronized, low latency streaming capabilitiesfor audio and video data that guarantees stream bandwidth reservation.TSN is a new generation of AVB, and backwards compatible with AVB.Throughout this disclosure, TSN and/or AVB support is identified by theacronym “TSN/AVB.” The bridge 102 includes multiple ports that connectwith multiple TSN/AVB end point devices 104. A given end point devicemay take the form of a computer, laptop, tablet, automotive embeddeddevice, video disk recorder, transcoder, and so forth. Each TSN/AVB endpoint device must be able to support a variety of TSN/AVB-related IEEEstandards including:

-   -   802.1AS: Timing and Synchronization for Time-Sensitive        Applications    -   802.1ASbt: gPTP Timing With Industrial Enhancements (supports        multiple time domains, single-step synchronization, and routers)    -   802.1Qat: Stream Reservation Protocol (SRP)    -   802.1Qav: Forwarding and Queuing for Time-Sensitive Streams    -   802.1Qbv and 802.1Qbu: Time Aware Scheduling and Frame        Preemption (provides ultra-low latency scheduled traffic in        switches, and jumbo frames to run over TSN/AVB)    -   802.1Qca and 802.1Qcc: Path Control and Reservation,        Enhancements to SRP (makes things fully Plug and Play)    -   802.1BA: Audio Video Bridging Systems    -   802.1CB: Redundant Streams, Frame Replication and Elimination        (provides enhanced reliability)    -   1722: A Layer 2 transport protocol for media talker and listener        endpoints    -   1733: A Layer 3 transport protocol for RTP and RTPC applications    -   P1722.1: Responsible for TSN/AVB device discovery, enumeration,        connection management and control for 1722-based devices.

In addition to using IEEE 1722.1 for discovery and enumeration as normalworkflow, alternative methods of discovery in conjunction with normalstream reservation and media transfer procedures may be used. One methoduses a separate electrical line for control, while data is stilltransferred through Ethernet. With another approach, talkers andlisteners publish themselves as services using mDNS protocol. Thus,alternative methods to IEEE 1722.1 may be employed for offloading to theEthernet controller as well as the standard AVDECC methods mentionedhere that we use throughout for illustration purposes.

With continued reference to FIG. 1, the multiple endpoint devices thatsupport the TSN/AVB Standards together form a TSN/AVB domain 106. Endpoint devices that do not support TSN/AVB services, such as end pointdevice 108, are outside of the TSN/AVB domain, and are not TSN/AVBcapable to the extent that certain Quality of Service standards areguaranteed. To enable TSN/AVB end point devices to communicate viaEthernet networks, Ethernet adapter cards are often employed.

FIG. 2 illustrates one specific embodiment of a TSN/AVB end point device202 in the form of a computer, and coupled to an Ethernet adapter card204. The computer 202 generally includes a computer processing unit(CPU) 206, memory (not shown) and software in the form of an operatingsystem 208, control applications 210, and a system kernel 212. Tosupport TSN/AVB-related services, the kernel generally includes timingand synchronization API 214, a streaming API 216, network protocolstack, commonly TCP/IP 218, drivers for media streaming like IEEE1722and RFC 3497 media 224, implementation of endpoint discovery,enumeration, connection and control protocol like IEEE 1722.1 or RFC2326 and Ethernet network adapter hardware driver 228. Thus, for someoperating modes, the kernel is capable of interacting with the CPU 206to support TSN/AVB-related processing. However, as explained below,power consumption and higher efficiency may be attainable in someoperating modes by offloading TSN/AVB discovery, enumeration andconnection management to the Ethernet network adapter card 204.Input/Output (I/O) hardware 230, such as a PCIe interface, provides fordata transfers between the CPU 206 and other devices, such as theEthernet network adapter card 204.

With continued reference to FIG. 2, the Ethernet adapter card 204includes an Ethernet media access controller (MAC) 232 and an Ethernetphysical layer device (PHY) 234. The MAC 232 includes AVDECC offloadhardware that support the relevant TSN/AVB Standards necessary to carryout TSN/AVB-related processing in lieu of processing by the computer CPU206. The MAC 232 employs processing resources such as a processor 242responsive to software including TSN/AVB control state machines 243,VLAN tagging hardware 244, QOS Engine 246 and Framer De-Framer 248 thatinterface with the TSN/AVB state machines 243.

Further referring to FIG. 2, for one specific embodiment, the EthernetPHY 234 takes the form of an NBASE-T Ethernet transceiver chip thatincludes a timestamper 246. The timestamper generates a timestamp, withrespect to a centralized time reference, for data that is transmitted orreceived. In this manner, time synchronization may be maintained betweenTSN/AVB end point devices.

FIG. 3 illustrates one specific embodiment of the Ethernet networkadapter card of FIG. 2, generally designated 300, corresponding to theEthernet network adapter card of FIG. 2 and showing many of the featuresillustrated in FIG. 2, albeit in physical form rather than logical form.The card 300 includes a media access controller (MAC) 302 that connectsto a physical device (PHY) 304 in the form of an Ethernet transceiver.The MAC 302 includes a micro-controller or processor 306 that employs aninput/output I/O interface 308, such as PCIe, and includes respectivetransmit and receive logic circuits 310 and 312. The logic circuitscouple to the PHY via an MII like KR interface such as (but not limitedto) XFI, USXGMII, XGMII, SGMII interface 314. The PHY includes a PHYprocessor 320, digital logic 322 and analog logic 324. The PHY includesa timestamper 325 (corresponding to the timestamper 246 of FIG. 2) forassociating a timing reference for data transferred between the MAC andPHY. A line interface 326 couples the Ethernet card to an Ethernetnetwork.

In operation, the Ethernet network adapter 300 carries out discovery,enumeration and connection management and audio video data framing andde-framing while minimizing usage of the end point host CPU 206 andmaking support of TSN/AVB on host operating system 208 unnecessary. FIG.4 illustrates steps employed during one embodiment of audio videodiscovery, enumeration, connection and streaming offload in a networkadapter. In the illustrated embodiment, AVDECC could be initialized, at402, by either an Ethernet link going up, switching to sleep mode withsleep proxy taking control on network link, or starting a TSN/AVBapplication.

With the Ethernet network adapter card 300 interfaced with the computer202, a user may desire to open a streaming application that may involve,for example, video data. As another possible scenario, Operating system208 switches the computer 202 to low power mode, passing network linkcontrol to MAC 232. An audio video endpoint managed by processor 242 isexposed as a discoverable entity according to a control protocol, at404. Discovery, enumeration and connection management state machines arethen managed by processor 242, at 406, allowing an AVDECC request forthe discoverable entity from network to be identified, at 408.Generally, an AVDECC request is handled by TSN/AVB-related drivers thathave been offloaded to the network adapter card, which initiates andmanages talker and listener state machines, at 410. More specifically,an end-to-end path for streaming the video data from its source to anend-point may be determined and network stream (and redundant stream)resources may be reserved, at 412 (such as various coder/decoders, fixeddata rates, variable data rates, VLANs, stream bandwidth, etc.).Generally, the stream and redundant stream reservations are negotiatedfor the end-to-end data transfer to ensure a certain Quality of Service(QoS).

With additional reference to FIG. 4, the Ethernet network adapterhardware may then be programmed, at 414, which generally involvesconfiguring the timestamper 246 in the PHY 234, and carrying outappropriate QoS and VLAN programming in the MAC 232. Once theprogramming is completed, the MAC 232 may report to the application thata successful path negotiation is complete, at 416. In one of theembodiments, path negotiation completion is reported to application 210,which runs on the host CPU 206. In other embodiment, completion isreported to software which runs on the embedded processor 242.

In some embodiments, for every packet that was modified by thetimestamper 246 and sent to the network, the MAC 232 collects timingreference information that was added to the packet and sends it to theAVB/TSN network endpoint device. In one of the embodiments, processor242 reads timing reference information from the timestamper 246,accumulates this information into data packets and send them to PCIhardware 230, to make it available to the Ethernet driver 228. Inanother embodiment, MAC 232 has dedicated hardware logic that reads thetime reference information from the timestamper 246 and sends it to thePCI hardware 230.

Further referring to FIG. 4, a network stream that has been opened, at418, may be using one or several of the network protocols like TCP/IP,IEEE 1722 by the various TSN/AVB-related extensions or drivers that havebeen offloaded into the network adapter MAC. The stream and redundantstream may then be used for media data transfers at 420.

Use of the network adapter card to identify the network topology andnegotiate the stream and redundant stream resources allows the computerCPU 206 to operate in a low-power mode, or allow it to handle othertasks while AVDECC and media stream processing are handled by theEthernet network adapter card 204. This also allows accessing theTSN/AVB network on hosts which do not have full support of TSN/AVBdiscovery, enumeration, connection management and control. Thus, byoffloading the TSN/AVB-related extensions or drivers into the MAC 232 ofthe Ethernet network adapter card, significant power savings may berealized.

Further referring to FIG. 4, for some embodiments, a network stream thathas been opened, at 418, may be using one or several of the networkprotocols like TCP/IP, IEEE 1722 by the various TSN/AVB-relatedextensions or drivers that have been offloaded into the network adapterMAC. The stream and redundant stream may then be used for media datatransfers at 420. Additionally, in some embodiments, the network adapterMAC includes offload hardware for adding stream identificationinformation to the packets being transmitted to the network. The networkadapter MAC also includes hardware for received stream identification,removing redundant frames stripping stream identification informationfrom the packets being received from the network. In one of theembodiments, stream identification information may be added to theframes as Redundancy tag defined in IEEE 802.1CB.

When received within a computer system via one or more computer-readablemedia, such data and/or instruction-based expressions of the abovedescribed circuits may be processed by a processing entity (e.g., one ormore processors) within the computer system in conjunction withexecution of one or more other computer programs including, withoutlimitation, net-list generation programs, place and route programs andthe like, to generate a representation or image of a physicalmanifestation of such circuits. Such representation or image maythereafter be used in device fabrication, for example, by enablinggeneration of one or more masks that are used to form various componentsof the circuits in a device fabrication process.

In the foregoing description and in the accompanying drawings, specificterminology and drawing symbols have been set forth to provide athorough understanding of the present invention. In some instances, theterminology and symbols may imply specific details that are not requiredto practice the invention. For example, any of the specific numbers ofbits, signal path widths, signaling or operating frequencies, componentcircuits or devices and the like may be different from those describedabove in alternative embodiments. Also, the interconnection betweencircuit elements or circuit blocks shown or described as multi-conductorsignal links may alternatively be single-conductor signal links, andsingle conductor signal links may alternatively be multi-conductorsignal links. Signals and signaling paths shown or described as beingsingle-ended may also be differential, and vice-versa. Similarly,signals described or depicted as having active-high or active-low logiclevels may have opposite logic levels in alternative embodiments.Component circuitry within integrated circuit devices may be implementedusing metal oxide semiconductor (MOS) technology, bipolar technology orany other technology in which logical and analog circuits may beimplemented. With respect to terminology, a signal is said to be“asserted” when the signal is driven to a low or high logic state (orcharged to a high logic state or discharged to a low logic state) toindicate a particular condition. Conversely, a signal is said to be“deasserted” to indicate that the signal is driven (or charged ordischarged) to a state other than the asserted state (including a highor low logic state, or the floating state that may occur when the signaldriving circuit is transitioned to a high impedance condition, such asan open drain or open collector condition). A signal driving circuit issaid to “output” a signal to a signal receiving circuit when the signaldriving circuit asserts (or deasserts, if explicitly stated or indicatedby context) the signal on a signal line coupled between the signaldriving and signal receiving circuits. A signal line is said to be“activated” when a signal is asserted on the signal line, and“deactivated” when the signal is deasserted. Additionally, the prefixsymbol “/” attached to signal names indicates that the signal is anactive low signal (i.e., the asserted state is a logic low state). Aline over a signal name (e.g., ‘<signal name>’) is also used to indicatean active low signal. The term “coupled” is used herein to express adirect connection as well as a connection through one or moreintervening circuits or structures. Integrated circuit device“programming” may include, for example and without limitation, loading acontrol value into a register or other storage circuit within the devicein response to a host instruction and thus controlling an operationalaspect of the device, establishing a device configuration or controllingan operational aspect of the device through a one-time programmingoperation (e.g., blowing fuses within a configuration circuit duringdevice production), and/or connecting one or more selected pins or othercontact structures of the device to reference voltage lines (alsoreferred to as strapping) to establish a particular device configurationor operation aspect of the device. The term “exemplary” is used toexpress an example, not a preference or requirement.

While the invention has been described with reference to specificembodiments thereof, it will be evident that various modifications andchanges may be made thereto without departing from the broader spiritand scope of the invention. For example, features or aspects of any ofthe embodiments may be applied, at least where practicable, incombination with any other of the embodiments or in place of counterpartfeatures or aspects thereof. Accordingly, the specification and drawingsare to be regarded in an illustrative rather than a restrictive sense.

We claim:
 1. An Ethernet adapter module for interfacing a networkendpoint device to an Ethernet network, the Ethernet adapter modulecomprising: a network endpoint interface for connecting to the networkendpoint device, the network endpoint device to perform Time SensitiveNetworking/Audio Video Bridging (TSN/AVB) related processing in a firstmode of operation; an Ethernet network interface for connecting to theEthernet network; and an Ethernet medium access controller (MAC), theEthernet MAC including a processor, Time Sensitive Networking/AudioVideo Bridging (TSN/AVB) logic to cooperate with the processor toselectively perform TSN/AVB-related processing that is offloaded fromthe network endpoint device, in a second mode of operation, in responseto an offload request from operating system software associated with thenetwork endpoint device.
 2. The Ethernet adapter module according toclaim 1, further comprising: frame sequencing logic to, in the secondoperating mode, perform frame sequencing operations consistent withstandard IEEE 802.1CB.
 3. The Ethernet adapter module according to claim1, further comprising: an Ethernet physical layer device (PHY) coupledto the Ethernet MAC including timestamp logic to apply a timingreference to transferred data; and wherein the Ethernet MAC accumulatesthe timing reference and feeds it back to the network endpoint device.4. The Ethernet adapter module according to claim 1, further comprising:control logic to, in the second operating mode, perform RTPC controlpacket operations consistent with standard IEEE
 1733. 5. The Ethernetadapter module according to claim 1, wherein the (TSN/AVB) logiccomprises: state machines that cooperate with the processor to (1)identify a TSN/AVB request from the network endpoint device, and (2)discover a network topology along which to transfer data between thenetwork endpoint device and a second network endpoint device inaccordance with a predetermined Quality of Service (QoS).
 6. TheEthernet adapter module according to claim 1, wherein the Ethernet MACfurther includes a clock slave state machine.
 7. The Ethernet adaptermodule according to claim 1, wherein the Ethernet PHY comprises anNBASE-T transceiver chip.
 8. The Ethernet adapter module according toclaim 5, wherein the state machines operate in accordance with at leastone standard from the group comprising IEEE 1722.1, 802.1BA, 802.1Qat,1588 PTPv2, 802.1AS, 802.1ASbt, 802.1Qbv, 802.1Qbu, 802.1Qca, 802.1Qccand 802.1CB.
 9. A system comprising: a first TSN/AVB network endpointdevice having processing hardware and a control application interface,the network endpoint device to perform Time Sensitive Networking/AudioVideo Bridging (TSN/AVB) related processing in a first mode ofoperation; an Ethernet adapter module for interfacing the first TSN/AVBnetwork endpoint device to an Ethernet network, the Ethernet adaptermodule including an Ethernet medium access controller (MAC), theEthernet MAC including a processor, Time Sensitive Networking/AudioVideo Bridging (TSN/AVB) logic to cooperate with the processor toselectively perform the TSN/AVB-related processing that is offloadedfrom the network endpoint device, in a second mode of operation, inresponse to an offload request from operating system software associatedwith the network endpoint device.
 10. The system according to claim 9,wherein the Ethernet adapter module further comprises: frame sequencinglogic to, in the second operating mode, perform frame sequencingoperations consistent with standard IEEE 802.1CB.
 11. The systemaccording to claim 9, wherein the Ethernet adapter module furthercomprises: an Ethernet physical layer device (PHY) coupled to theEthernet MAC including timestamp logic to apply a timing reference totransferred data; and wherein the Ethernet MAC accumulates the timingreference and feeds it back to the network endpoint device.
 12. Thesystem according to claim 9, wherein the Ethernet adapter module furthercomprises: control logic to, in the second operating mode, perform RTPCcontrol packet operations consistent with standard IEEE
 1733. 13. Thesystem according to claim 9, wherein for the second operating mode, thefirst TSN/AVB network endpoint device operates in a reduced-power modewhile the Ethernet adapter module performs the TSN/ABV-relatedprocessing.
 14. The system according to claim 9, wherein the firstTSN/AVB network endpoint device comprises a computer.
 15. A method ofoperation between a TSN/AVB network endpoint device and an Ethernetnetwork adapter, the method comprising: interfacing the Ethernet adaptermodule with the TSN/AVB network endpoint device to an Ethernet networkcomprising: opening an application with the TSN/AVB network endpointdevice; connecting a network endpoint interface to the TSN/AVB networkendpoint device; in a first mode of operation, performing, by theTSN/AVB network endpoint device, TSN/AVB related processing; connectingan Ethernet network interface to the Ethernet network; and in a secondmode of operation, selectively performing, by an Ethernet medium accesscontroller (MAC) including a processor, Time Sensitive Networking/AudioVideo Bridging (TSN/AVB) logic cooperating with the processor,TSN/AVB-related processing that is offloaded from the network endpointdevice, in response to an offload request from operating systemapplication associated with the network endpoint device.
 16. The methodaccording to claim 15, further comprising: in the second operating mode,performing frame sequencing operations with the Ethernet network adapterconsistent with standard IEEE 802.1CB.
 17. The method according to claim15, further comprising: applying a timing reference to transferred datawith timestamp logic in an Ethernet physical layer device (PHY); andaccumulating the timing reference with the Ethernet MAC and feeding itback to the TSN/AVB network endpoint device.
 18. The method according toclaim 15, further comprising: in the second operating mode, performingRTPC control packet operations with control logic consistent withstandard IEEE
 1733. 19. The method according to claim 15, wherein theprocessing of the TSN/AVB services comprises: discovering a networktopology for transferring TSN/AVB data between the TSN/AVB networkendpoint device and a second TSN/AVB network device, reserving streamsfor transferring the TSN/AVB data, and timestamping the TSN/AVB data.20. The method according to claim 15, wherein the TSN/AVB networkendpoint device includes a processor, and wherein the processor operatesin a low-power mode while the Ethernet network adapter carries out theprocessing of the TSN/AVB services.